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The Sierra Forest Voice

Web Edition
Vol. 7, No. 1, March 26, 2014

Status Update for the California Spotted Owl

Assessment of population trends of the owl and the extent to which management practices are affecting its commercially valuable forest habitat are controversial subjects. The California spotted owl (Strix occidentalis occidentalis) is one of three rare subspecies, yet it is the only one that is not protected by the Endangered Species Act. Population studies indicate that the California spotted owl population is rarer than the Northern spotted owl (Strix occidentalis caurina, listed as threatened in 1990, and perhaps even rarer than the Mexican spotted owl, Strix occidentalis lucida, listed in 1993. Twice, Sierra Forest Legacy and the Center for Biological Diversity, along with fourteen other conservation organizations, petitioned the U.S. Fish and Wildlife Service to list the California spotted owl for protection under the federal Endangered Species Act--first in 2000, then in 2004. In both instances the agency denied the petitions, concluding that listing was not warranted (U.S. Fish and Wildlife Service 2003 and 2006).

When making a determination if a species warrants listing, the U.S. Fish and Wildlife Service does not focus on historical declines in abundance and/or distribution, but rather if the species is being propelled toward extinction or endangerment in the foreseeable future. In the last FWS decision, the agency focused on the results of a meta-analysis of mark-recapture population studies conducted from 1990 through 2005 (Blakesley 2006). Ultimately, the population analyses was inconclusive, but the agency would state in the decision: “The best-available data indicate that California spotted owl populations are stationary throughout the Sierras” (USFWS 2006).

Since 2006, new analyses of California spotted owl demographics, also building on the long-term dataset analyzed in the previous meta-analyses, provide conclusive evidence that the species has been declining on all three National Forest monitoring sites since the early 1990s (Conner et al. 2013; Tempel and Gutierrez 2013, Tempel 2014).

Conner et al (2013) suggest that the method used to estimate the rate of population change in the meta-analyses is confounded by an inherent susceptibility to making a “Type II” error, or an inability to detect a decline or change when in fact, one has actually occurred. In essence, the U.S. Fish and Wildlife’s decision not to list the species was not because the Forest Service management activities were not affecting it, it was because the population trend data were inconclusive.

Conner’s team used the same data as the previous meta-analysis (1990-2005) and additional survey data from 2005-2011, for the Lassen, Sierra, and Sequoia-Kings Canyon Park study areas. They compared and evaluated several different statistical methods to arrive at the annual population rate of change. The results suggest that between 1990 and 2011 the spotted owl population on the Lassen National Forest study area declined by 21 percent and the population on the Sierra National Forest study area declined by 11 percent, while the population on the Sequoia-Kings Canyon National Park study area, where logging activities are minimal, increased by 22 percent. To increase precision, Conner et al. (2013) estimated the probability that the populations on the three study sites were declining, finding that the probabilities of a population decline greater than or equal to 15 percent over 18 years was 0.69 on the Lassen and 0.40 on the Sierra study areas and 0.04 over 17 years on the Sequoia-Kings Canyon study area; while the probabilities the population was stable or increasing were 0.07 on the Lassen, 0.22 on the Sierra, and 0.82 on the Sequoia-Kings Canyon.

Tempel and Gutierrez (2013) calculated occupancy and abundance using data from the Eldorado National Forest study area sites from 1993 to 2010. Using occupancy (detection-nondetection) modeling (MacKenzie et al. 2003) to determine how occupancy changed over the study period, they found that owl occupancy declined by 30 percent, territory extinction increased over time, and colonization rates were insufficient to maintain occupancy at its initial level. They then compared the occupancy modeling results with annual rates of population change from mark-recapture data, and found that the data closely matched, but the occupancy data were much more conclusive. The results of Tempel and Gutierrez (2013) justify the use of occupancy (detection-nondetection) studies as a means of determining California spotted owl population trends, which is a much more cost-effective study design than the mark-recapture studies used to determine change in population. Since the data collection methods for the Lassen, Sierra, and Sequoia-Kings Study areas are similar to the Eldorado, the opportunity also exists to model changes in occupancy over the study period at those sites. Citing Seamans and Gutierrez (2007), the authors suggest that the lack of colonization on the Eldorado study area may be attributable to habitat alteration during the study period (e.g., logging, high-intensity wildfire) affecting the quality of vacant owl territories.

Most recently, in his doctoral dissertation on California spotted owl demographics in the Eldorado Study Area, owl researcher Doug Tempel (2014) describes another data analysis technique designed to increase precision and reduce the uncertainty that has plagued previous analyses. Using the new integrated population model that incorporated count, reproductive, and mark-recapture data, Tempel found a clear population decline of 50 percent between 1990 and 2012 with 95% credible intervals well below 1.0. Summarizing the status of the owl in his dissertation, Tempel concludes, “Finally, my results suggested that the U.S. Fish and Wildlife Service (2006) may need to reevaluate their recent decision not to list the California spotted owl under the Endangered Species Act because population declines are becoming apparent and it is not clear if USFS management actions are related to this decline.”

We believe that the steady decline of the owl that has been observed over the past 20 years is unfortunately likely to persist due to the continuation of forest management practices that reduce the quality and quantity of habitat, and the increasing likelihood of large high severity wildfires as a result of wildfire exclusion and climate change. These are trends that FWS is going to have to base future decisions on.

Quotable Quotes

Under this paradigm, logging would be explicitly designed to achieve or maintain ecological goals. Kevin McKelvey and C. Philip Weatherspoon, in the CASPO Technical Report (GTR -133), 1992.

These are our lands...And they will be our lands and our children's and our children's and our children's children's lands far into the future unless we, as a people, through carelessness or apathy or conscious choice, allow that precious heritage to be sold or traded away for pottage. --Jack Ward Thomas, 1996

The problems that we have created cannot be solved at the level of thinking that created them.
Albert Einstein

Forest Assessment and Monitoring Under the 2012 Planning Rule

Forest monitoring is the key to good land management because it provides information about conditions and trends of forest resources, wildlife and habitats, identifies the causes of altered conditions, and provides the basis for effective management.

The new Planning Rule, together with the pending Directives (Forest Service Manual 1900 and Forest Service Handbook 1909.12, due in May 2014) provide the regulatory framework for land management plans (LMPs), amendments and revisions in accordance with the requirements of the National Forest Management Act of 1976. The Forest Service in California has begun revising forest plans in the Southern Sierra Nevada using the new rule.

In the Sierra Nevada forests, LMPs were created in the late 1980s and early 1990s, and have been amended twice, in 2001 and 2004, but only in five issue areas: old forest and associated species; aquatic, meadow and riparian ecosystems and associated species; fire and fuels management; lower Westside hardwoods ecosystems; and noxious weed management. These plans are now outdated and it is essential that new forest plans contain an effective monitoring strategy to inform adaptive management. The 2012 Forest Planning Rule provides improved guidance for the required monitoring plan, as well as other important plan components.

The Forest Assessment process described in the 2012 Planning Rule at 36 CFR § 219.6 provides the instructions for considering the breadth of relevant, existing information that can be used to inform the new plans. Monitoring information including the best available scientific information must be documented in the assessment process. The role of monitoring and scientific research in understanding changed conditions and trends of a wide range of resources cannot be understated. The Need for Change can only be addressed if there is information available to inform the Forest Service decision making process.

While the responsible official has the discretion to determine the scope and scale of the Forest Assessment, that discretion is limited by the language in § 219.6. In § 219.6 (b) the "responsible official shall identify and evaluate existing information relevant to the plan area for the following: (1) Terrestrial aquatic ecosystems and watersheds; (2) Air, soil, and water resources and quality; (3) System drivers, including dominant ecological processes, disturbance regimes, and stressors, such as natural succession, wildland fire, invasive species, and climate change; and the ability of terrestrial and aquatic ecosystems in the plan area to adapt to change; (4) Baseline assessment of carbon stocks; (5) Threatened, endangered, proposed and candidate species, and potential species of conservation concern present in the plan area; (6) Social, cultural, and economic conditions; (7) Benefits people obtain from the NFS planning area (ecosystem services); (8) Multiple uses and their contribution to local, regional, and national economies; (9) Recreation settings, opportunities and access, and scenic character; (10) Renewable and nonrenewable energy and mineral resources; (11) Infrastructure, such as recreational facilities and transportation and utility corridors; (12) Areas of tribal importance; (13) Cultural and historic resources and uses; (14) Land status and ownership, use and access patterns; (15) Existing designated areas located in the plan area including wilderness and wild and scenic rivers, and potential need and opportunity for additional designated areas."

This more comprehensive list of issues is an important change in the new rule, since issues such as climate change impacts, carbon stocks and ecological services were never thought of, let alone considered by the Forest Service, in the pre-internet days of the late-1980s when the current plans were developed.

Getting to Five-Star Monitoring for Forest Plans

The 2012 Planning Rule at § 219.12 contains the instructions for building a forest plan-level monitoring program. The purpose is to inform the responsible official if changes in plan components or other plan content that guide management in the plan area may be needed 36 CFR 219.12 (a) (1). Importantly, the new era of monitoring plans must be done in coordination with the Forest Service Research Branch.

Monitoring plans must set out the monitoring questions and indicators to inform the management of resources in the plan area. These are based upon one or more desired conditions, objectives, or other plan components in the plan area.

The Planning Rule at 36 CFR 219.12 (a) (5) requires that each plan monitoring program must contain one or more monitoring questions and associated indicators addressing the following issues: (1) status of select watershed condition; (2) the status of select ecological conditions including key characteristics of terrestrial and aquatic ecosystems; (3) the status of focal species to access the ecological conditions required under § 219.9 (diversity requirements); (4) the status of a select set of ecological conditions required under § 219.9 to contribute to the recovery of federally listed threatened and endangered species, conserve proposed and candidate species, and maintain a viable population of each species of conservation concern; (5) the status of visitor use, visitor satisfaction, and progress toward meeting recreation objectives; (6) measurable change in the plan area related to climate change and other stressors that may be affecting the plan area; (7) progress toward meeting the desired conditions and objectives in the plan, including providing multiple use opportunities; (8) the effects of each management system to determine that they do not substantially or permanently impair the productivity of the land.

Broad Scale Monitoring

The new Planning Rule at 36 CFR § 219.12 (b) spells out direction for landscape-scale monitoring strategies developed at the Regional level to address monitoring questions at a broader geographic area. Sierra Forest Legacy is advocating for these monitoring plans for wide ranging species such as the California spotted owl, Pacific fisher, and for issues such as fire use and effects across the Sierra Nevada.

Monitoring Best Practices -- Key Technical Reports

There are volumes written on monitoring wildlife but few are as comprehensive and thoughtful as these general technical reports from Forest Service Research. It will be important for the conservation community to understand the basic tenants of monitoring plan design, and Strategies for Monitoring Terrestrial Animals and Habitats (GTR-161) is a good place to start.

New monitoring plans must be developed for all national forests within four years of this new rule (2016) or as soon as practicable to meet the intent of § 219.12 (c). The GTR has sections on background and current efforts; developing monitoring questions; creating an integrated monitoring plan; sampling design and statistical considerations and guidelines; applying monitoring to management, including adaptive management; organizational considerations; and critical elements for successful monitoring (what we are calling 5 star monitoring plans). While this may look highly complicated, our Forest Planning coalition will need to be up-to-speed with the best Forest Service thinking on the subject of bioregional and plan level monitoring to fully engage and support development of robust monitoring plans in the upcoming revisions.

Challenges to successful monitoring (from GTR-161):

Monitoring and evaluation is viewed as another "new" program which will require more money, more time, and more people-resources which are already stressed.

Monitoring and evaluation requirements often are not based on clear objectives, do not address key management questions or do not address key issues.

There is no incentive for doing monitoring and evaluation, and little or no perceived risk for not doing it.

Monitoring and evaluation is not recognized as an integral part of target accomplishment.

Effective teamwork within the Forest Service and with other agencies, partners and public is not readily apparent.

Appropriate scientific methods frequently are not used in conducting monitoring and evaluation.

Key recommendations (from GTR-161):

Make a national commitment to improve monitoring of terrestrial animals and their habitats.

Ensure that all monitoring contributes to adaptive management by exploring both the causes for trends and alternative scenarios that could reverse unfavorable trends.

Ensure that all monitoring complies with USDA Data Quality Guidelines.

Implement Regional monitoring strategies that integrate habitat and population monitoring. Monitoring habitat alone will rarely be sufficient for adaptive management because habitat relationships are not well understood and may not be predictable.

Adopt and integrate three types of monitoring (context, targeted, and cause-and-effect).

Use sound ecological principles and risk assessment to prioritize and design monitoring activities.

Recognize that monitoring is multi-scalar. Coordinate across ecological and administrative scales, with emphasis on the role of the Regions.

Establish appropriate roles and coordination for NFS and R&D from WO through Forest levels.

Use partnerships and interagency coordination to accomplish monitoring objectives.

Ensure that individuals and teams responsible for monitoring, development, and oversight have appropriate skills

There are few issues more important to improved forest management than monitoring. The Forest Service research branch has done a great job compiling the information that is sorely needed today to implement "the best available science" on the ground. Click on the book covers below to download Strategies for Monitoring Terrestrial Animals and Habitats (GTR-RMS-161), Multiple Species Inventory and Monitoring Technical Guide (GTR-WO-073) and A Technical Guide for Monitoring Wildlife Habitats (GTR-WO-89).

Adaptive Management

Finally, a word on Adaptive Management--an often-used term when applied to Forest Service planning, but rarely defined in the context of how monitoring information is used to inform future management decisions.

For example, Step 6 in the diagram below implies that action will be taken, but currently there are no specific criteria--which are both transparent and collaborative--that determine which, and when, new information will trigger new management strategies. Adjusting management based on evaluation of results of monitoring (or new scientific information) is key to informed decision making. Currently, the new planning rule § 219.12 (d) calls for a biennial evaluation of monitoring information and a monitoring evaluation report § 219.12 (d) (2) that is to inform adaptive management decisions in the plan area. Sierra Forest Legacy has made recommendations to the Forest Service for a transparent, collaborative, science-based process to examine and make independent recommendations to managers regarding plan updates.

The process for how new information is considered is key to open, transparent planning and land management. As the new plans come on line and monitoring is initiated we will need to be diligent and actively engaged to hold the Forest Service to its promise to maintain current, science-based, adaptive plans in the future.

News Bytes from the Front

Update: Revising the Forest Plans for the Inyo, Sequoia and Sierra National Forests

The Forest Service is well along in the process to revise the forest plans on the Inyo, Sequoia, and Sierra national forests. These forests are referred to as "early adopters" and are among the first in the nation to undergo the forest plan revision under the new planning rule adopted in 2012. The plan revision effort is a 3-4 year process intended to result in a forest plan that meets the direction to provide for the ecological integrity of the national forest and provide for sustainable benefits to the human community. The Forest Service will be preparing a single environmental impact statement (EIS) for the forest plans for all three forests.

To date, the Forest Service has produced a science synthesis, bioregional assessment for the Sierra Nevada, forest assessments for each national forest (Inyo, Sequoia, and Sierra) and a preliminary analysis that describes what they see as the need to change the current forest plans, and some examples of desired conditions for these national forests. We expect that in early April 2014 that the Forest Service will publish the Notice of Intent (NOI) to prepare an environmental impact statement (EIS). This notice will initiate the formal National Environmental Policy Act (NEPA) component of the revision process. See announcement below for workshops that the Forest Service is hosting on the scoping notice.

SFL and our conservation partners have been actively engaged in reviewing and commenting on the assessments, and the "need for change" statement produced by the Forest Service. We have serious concerns about the lack of detail provided in the assessments for some critical resources, e.g., at-risk species and ecological conditions of meadows and riparian habitats. We also found that there was a lack of integration in the analyses of habitat conditions needed to support at-risk species and the landscape-scale conditions reported in the assessments. The detailed comments submitted by our coalition can be downloaded from the SFL website (see links below).

Our comments on the "Preliminary Need for Change Analysis" highlighted our concerns that the scope of the analysis was too narrow and the analysis to support the change document too shallow. Critical aspects of the forest environment, such as roads and infrastructure, were not addressed in the change analysis, and the evaluation of other critical resources was incomplete.

At this point in the process, we are in active discussions with the Forest Service to extend the time line for the revision process. We believe there is a need to improve the assessment documents and build into the coming two years more opportunities for stakeholders to review the draft plan and alternatives, and the draft monitoring plan. A more thoughtful and integrated approach is needed now as the components of the plan are being developed, to ensure that these revised plans accomplish the mandate to provide for the ecological integrity of these ecosystems.

Actions to enhance habitat diversity and promote complex early seral conditions; and

Use of the Citizen's Roadless Area Inventory, assembled by California Wilderness Coalition and its partners, to evaluate potential wilderness areas and to complete habitat connectivity analyses. (See maps of these roadless areas for the Sierra and Sequoia national forests).

Read all the documents linked here, and more background on the forest plan revisions, here at the SFL website.

Announcements

Notice of Intent -- Coming Soon

The U.S. Forest Service's Pacific Southwest Region will host a series of public meetings as it begins the National Environmental Policy Act (NEPA) process of forest plan revisions for the Sierra, Sequoia and Inyo National Forests. A Notice of Intent, which marks the beginning of the formal public scoping period, will be published in early April.

These public meetings will focus on the revision of the three Early Adopter Forests Land Management Plans. The meetings are designed to share information on the Notice of Intent, which includes the purpose and need and proposed action. These meetings also notify the public and tribal communities that the Notice of Intent begins the formal NEPA process, including a 30 day scoping period. Scoping comments help refine the proposed action, identifying preliminary issues, and identifying interested and affected persons.

The Sierra, Sequoia and Inyo forest plan revisions will be completed through the development of one environmental impact statement. The final EIS will result in three separate Records of Decision and three separate forest plans. Forest Supervisors will remain the responsible officials for making decisions on their specific forest plans.

"This next round of public meetings gives the Forest Service another opportunity to share information about the forest plan revision process, explain the key themes of each forest plan to be revised, and gather public comment," said Regional Forester Randy Moore.

This is the last year for the Sierra Nevada Adaptive Management Project, or SNAMP, in which Sierra Forest Legacy has been participating since its beginnings in 2005. The project was designed to fulfill the 2004 appeal decision of the Sierra Nevada Framework that required an adaptive management and monitoring program in the national forests of the Sierra Nevada. The result has been a collaboration between scientists, agency staff, and public stakeholders to develop, implement, and test adaptive management processes through testing the efficacy of hazardous fuel treatment projects focused on the Pacific fisher and California spotted owl; water; fire and forest health. The results of California spotted owl monitoring are discussed in the owl status update discussed here in this newsletter, and you can read a summary of the latest owl monitoring research here. Read an update on Fisher monitoring here.

Members of the public with knowledge and interest in natural resource management or biodiversity concerns are encouraged to get involved.

Learning Corner

Sierra Forest Legacy Bookshelf

This is a chronicle of the Great Fire of August, 1910, a series of fires that blew up and became a massive fire that swept across approximately 3 million acres of northeast Washington, northern Idaho, and western Montana, destroying entire towns and killing 87 people. Author Timothy Egan, New York Times columnist and winner of a National Book Award, provides a riveting account of the days surrounding the fire from the points of view of several people, all very colorful characters, who lived through it. Of particular interest is the heroic story of Ed Pulaski, for whom--as every Forest Service employee knows--a fire fighting tool was subsequently named. Pulaski was an early recruit in the first years of the fledgling U.S. Forest Service, and his quick thinking and forestry experience helped him to save the lives of 40 men engulfed by the fire.

The historical context leading up to the fire sheds light on the roots of resentment towards the Forest Service that linger today. The early forest rangers, called "Green Rangers" or "Little Gifs" were underfunded, understaffed, and lacked basic equipment, but they were solely responsible not only for fire fighting, but for ousting hardened criminals from the newly created public forest lands. Illegal mining and timber theft were common, and gamblers, outlaws and hustlers of all kinds frequently set up shop along the few roads running through the west's forests, sometimes forming entire illegal towns. Violence and threats of violence were a daily liability on the job. Outraged by government proposals to restrain unfettered exploitation of the abundant resources in the western states, resentment was promoted by the robber barons and cattle kings of the time, and they used their money and influence to buy "cops and courts, newspaper editors and ministers, grand juries-any source of opposition or fair play." The few foresters hired to manage the forests were mostly young and idealistic followers of a new conservation ethic, graduates of the Yale School of Forestry and fostered by their benefactor and mentor, Gifford Pinchot. Pinchot had been appointed by his close friend President Theodore Roosevelt to be the first Chief of the Forest Service; both were deeply committed to protecting wild nature, though they shared the understanding that public forests could provide multiple benefits that included a sustainable level of logging for the lumber needs of the nation.

Photo right: Gifford Pinchot, first Chief of the U.S. Forest Service

The telling of the Great Fire of 1910 is interesting enough, but the real story behind the Big Burn is the friendship of Roosevelt and Pinchot, and the conservation ethic that drove them. Roosevelt insisted that the "rights of the public outweigh private rights" and "The forest reserves should be set apart forever for the use and benefit of our people as a whole and not sacrificed to the shortsighted greed of a few." Together, Roosevelt and Pinchot succeeded in establishing a network of wildlife refuges, national parks, and national forests, despite aggressive opposition by the large corporations, called syndicates and trusts in that era. To gain support for his policies, Roosevelt traveled throughout the land delivering speeches with his characteristic passion, and winning the presidency by a landslide in 1904. Together with Pinchot and their mutual friend John Muir, despite great odds, they succeeded in gaining the public support they needed to make the preservation of the nation's forests and water "the most vital internal question of the United States." All told, the Roosevelt administration established protection for 230,000,000 acres of forests and wetlands that included 150 national forests, 51 bird refuges, 5 national parks, and 18 national monuments.

After the Great Fire, Congress was persuaded through active campaigning by Pinchot and Roosevelt to support a dramatic increase in funding for the fledgling U.S. Forest Service. Sadly, Pinchot was devastated later in life as he watched the Forest Service turn into a servant of the logging industry. He had hand-picked William Greeley to lead Region 1 of the Forest Service as its first regional forester. Over time, Pinchot and the other rangers came to understand the role of fire in keeping forests thinned, but Greeley's experience during the Great Fire had the opposite effect: he came to view fire as Satanic (he was also a religious fanatic). In 1920, he was appointed the third Chief of the Forest Service, and he made fire suppression the primary mission for the agency. Logging was increased tenfold, and clearcutting became the dominant harvest method. In 1937, when Pinchot visited the rich woods in western Oregon, he saw "Absolute destruction...Mostly a clean sweep, taking everything...The men who did this are nothing less than public enemies."

The Big Burn provides an important historical context for many of the issues that we struggle with today as we work for a more perfect conservation ethic. This book is likely to inspire many towards further inquiry.

Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty -- Albert Einstein

Spotlight on Species:

Northern Flying Squirrel (Glaucomys sabrinus)

The northern flying squirrel is a nocturnal arboreal squirrel occurring throughout the northern latitudes of the United States and Canada. They do not actually fly, but glide from tree to tree by spreading a flap of skin called a patagium. They have thick brownish fur on their upper body, grey on the flanks and whitish underneath. They have large eyes, flat tails, and long whiskers. The adult northern flying squirrel measures from 25 to 37 cm long, and their weight can range from 110 to 230 grams.

There is considerable evidence that flying squirrels are more abundant in forests with many large live trees, many large dead trees (snags), well-developed understories, and many large logs on the ground. In the Sierra Nevada, where conditions are relatively xeric (dry) compared to elsewhere within the species' range, higher densities of flying squirrels are often found in relatively close proximity (less than 150 meters) to perennial streams. It is believed that the correlation between this species and perennial streams in the Sierra Nevada is due to higher soil moisture and other microclimate conditions in riparian areas that increases the abundance of the squirrels primary food source, truffles. Truffles are the fruiting bodies of certain subterranean fungi.

Average home range sizes of approximately 9 to 29 hectares (22 to 72 acres) have been recorded in the Sierra Nevada, with individual home ranges overlapping, both within and between sexes, suggesting individuals share foraging areas. On the Sierra National Forest in the central Sierra Nevada, these squirrels were found selecting taller and larger than expected diameter conifers (red firs in particular) and snags for nesting. On the Plumas National Forest in the northern Sierra, one study found that they selected hardwoods (black oaks) more often than expected compared to all other available trees and snags. Larger trees, snags, and hardwoods are more likely to have woodpecker or fungal cavities, or other decay features that allow for internal nesting, and thereby offer protection from predation and environmental extremes. They do not create their own cavities, relying on naturally created cavities or cavities created and abandoned by woodpeckers.

Photo below: forest truffles, photo by U.S. Forest Service Pacific Southwest Research

Northern flying squirrels play several important roles in forest ecosystems. They are one of the most important food prey species for several old forest dependent species, including California spotted owls, Pacific fishers, and American martens. In addition, flying squirrels eat, store, and distribute truffle spores throughout the forests they inhabit. Truffles are critical to forest health because these fungi form mycorrhizal relationships with trees, a symbiotic (mutually beneficial) relationship that provides the trees with otherwise unavailable water and nutrients from the soil, while the fungi receive carbohydrates from the tree roots. Trees with mycorrhizal fungi associations grow larger and faster, and they are less susceptible to drought and disease.

The primary threats to this species are incompatible forest management practices, large high-severity wildfires, and climate change. Forest management practices and large high-severity wildfires can reduce canopy closure and large conifer and hardwood tree densities, reducing habitat quality and quantity. It has been shown that northern flying squirrel abundance is reduced by forestry practices that influence the structure or age of residual stands, both in the short and the longer term, and abundance has also been shown to be reduced in partially harvested areas compared to uncut stands. Prescribed fire may have short-term (less than 8 years) negative effects on abundance by reducing the frequency and biomass of their primary food source, truffles. Climate-driven changes in fire regimes are projected to include increases in fire frequency, area, and intensity which are expected to result in loss of late-seral habitat. Because northern flying squirrels are thought to be resource and dispersal limited these threats make small and isolated populations more vulnerable to local extinction.

Conservation Measures

Survey for flying squirrels within 150 meters of perennial streams and on mesic sites prior to implementing activities that may affect the species to determine if species specific measures should be implemented.

Limit fuel treatments on mesic sites and within 150 meters of perennial streams occupied by flying squirrels to latter fuel reduction and infrequent (greater than 10-15 years between fire events) low intensity prescribed burning (less than 10 percent mortality in the dominant and co-dominant trees).

Increase canopy cover and the number of large trees and snags on unoccupied sites within 150 meters of perennial streams, on mesic sites, and adjacent to occupied sites.

The Northern flying squirrel is considered a management indicator species for all ten National Forests in the Sierra Nevada. The species is currently being monitored on the Plumas and Lassen National Forests though a multi-year monitoring effort. It is not considered a game species and it is illegal to kill or capture a northern flying squirrel.

Watch a National Geographic video clip of the Northern flying squirrel, here.

Enjoy learning more about flying squirrels from this website created by a Canadian team.

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Help Protect Our Sierra Nevada Forests

The work we do to protect the forests, with all of their unique and rare plants and animals, and the many wild places of the Range of Light cannot be done without the generosity of our supporters. Please help us to keep up our efforts. You can make a safe and secure donation from this website. Thanks to all who have so generously supported our work - together we form a multitude of voices. Join us in saying, "Si, se puede" on behalf of the wild forests of the Sierra Nevada.

"A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it does otherwise."
~Aldo Leopold